Part D, also known as the Medicare prescription drug benefit, is the part of Medicare that provides prescription drug coverage. The benefit is optional to most and provided only by private companies. You can get Part D coverage either through a stand-alone prescription drug plan (PDP) or a Medicare Advantage Prescription Drug Plan (MAPD)—a Medicare private health plan (Part C) that offers Medicare prescription drug coverage. You must choose Part D coverage that works with your Medicare health benefits. People who enroll in Part D pay a monthly premium in addition to their Part B premium. See also: Private Plan Card.